Artesian conditions in the Chilterns Chalk aquifer (North West of the London Basin) and the implications for surface water - groundwater interactions

2021 ◽  
pp. SP517-2020-144
Author(s):  
Alessandro Marsili ◽  
Ilias Karapanos ◽  
Mahmoud Jaweesh ◽  
Daniel R. Yarker ◽  
Eleanor M. Powers ◽  
...  
Keyword(s):  
River Flow ◽  
Regional Scale ◽  
Tectonic Stress ◽  
Specific Information ◽  
Groundwater Abstraction ◽  
North West ◽  
Geophysical Logging ◽  
Flow Response ◽  
Rock Strata

AbstractThe Chalk is a principal aquifer which provides an important resource in Southeast England. For two centuries, it allowed the establishment of a thriving watercress-growing industry, indirectly through diverted stream flow and directly, through the drilling of flowing artesian boreholes. The distribution of artesian boreholes across different catchments, suggests a regional control on vertical groundwater flow within the New Pit and Lewes Chalk units. Interrogation of location-specific information points to the confining role of a few key marls within the New Pit Chalk Formation, which can be traced up-catchment to where they naturally outcrop or have been exposed by quarrying. Evidence is found in geophysical logging of a number of boreholes across catchments, confirming a consistent pattern of the spatial distribution of such key markers. When tectonic stress was applied to the various Chalk Formations, the marl bands would have reacted producing more plastic deformation and less fractures in comparison with rigid rock strata. Such scenario would have created the conditions for secondary aquifer units, giving the Chalk confining or semi-confining hydraulic characteristics on a regional scale. This conceptual understanding helps explain the reasons that the river flow response to reductions in groundwater abstraction varies across the flow duration curve.

scholarly journals Role of glaciers in watershed hydrology: a preliminary study of a "Himalayan catchment"

2010 ◽  
Vol 4 (1) ◽  
pp. 115-128 ◽  
Author(s):  
R. J. Thayyen ◽  
J. T. Gergan
Keyword(s):  
Mass Balance ◽  
River Flow ◽  
Initial Increase ◽  
Glacier Mass Balance ◽  
Mountain Range ◽  
Humid Climate ◽  
Flow Response ◽  
Sustainable Water Resources Management ◽  
South West Monsoon

Abstract. A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November–April) and south-west monsoon in summer (June–September) dominating the regional hydrology. Such catchments are defined as "Himalayan catchment", where the glacier meltwater contributes to the river flow during the period of annual high flows produced by the monsoon. The winter snow dominated Alpine catchments of the Kashmir and Karakoram region and cold-arid regions of the Ladakh mountain range are the other major glacio-hydrological regimes identified in the region. Factors influencing the river flow variations in a "Himalayan catchment" were studied in a micro-scale glacier catchment in the Garhwal Himalaya, covering an area of 77.8 km2. Three hydrometric stations were established at different altitudes along the Din Gad stream and discharge was monitored during the summer ablation period from 1998 to 2004, with an exception in 2002. These data have been analysed along with winter/summer precipitation, temperature and mass balance data of the Dokriani glacier to study the role of glacier and precipitation in determining runoff variations along the stream continuum from the glacier snout to 2360 m a.s.l. The study shows that the inter-annual runoff variation in a "Himalayan catchment" is linked with precipitation rather than mass balance changes of the glacier. This study also indicates that the warming induced an initial increase of glacier runoff and subsequent decline as suggested by the IPCC (2007) is restricted to the glacier degradation-derived component in a precipitation dominant Himalayan catchment and cannot be translated as river flow response. The preliminary assessment suggests that the "Himalayan catchment" could experience higher river flows and positive glacier mass balance regime together in association with strong monsoon. The important role of glaciers in this precipitation dominant system is to augment stream runoff during the years of low summer discharge. This paper intends to highlight the importance of creating credible knowledge on the Himalayan cryospheric processes to develop a more representative global view on river flow response to cryospheric changes and locally sustainable water resources management strategies.

scholarly journals Role of glaciers in watershed hydrology: ''Himalayan catchment'' perspective

2009 ◽  
Vol 3 (2) ◽  
pp. 443-476 ◽  
Author(s):  
R. J. Thayyen ◽  
J. T. Gergan
Keyword(s):  
Mass Balance ◽  
River Flow ◽  
Glacier Mass Balance ◽  
Mountain Range ◽  
River Flows ◽  
Discharge Data ◽  
Flow Response ◽  
Himalayan Glacier ◽  
South West Monsoon

Abstract. A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November–April) and South-West monsoon in summer (June–September) dominating the regional hydrology. Such catchments are defined as ''Himalayan catchment'', where the glacier melt water contributes to the river flow during the period of annual high flows produced by the monsoon. Other two major glacio-hydrological regimes of the Himalaya are winter snow dominated Alpine catchments of the Kashmir and Karakoram region and cold-arid regions of the Ladakh mountain range. Factors influencing the river flow variations in a ''Himalayan catchment'' were studied in a micro scale glacier catchment in the Garhwal Himalaya, covering an area of 77.8 km2. Discharge data generated from three hydrometric stations established at different altitudes of the Din Gad stream during the summer ablation period of 1998, 1999, 2000, 2001, 2003 and 2004. These data has been analysed along with winter/summer precipitation, temperature and mass balance data of the Dokriani glacier to study the role of the glacier and precipitation in determining the runoff variations along the stream continuum from the glacier snout to 2360 m a.s.l. Study shows that the inter-annual runoff variations in a ''Himalayan glacier catchment'' is directly linked with the precipitation rather than mass balance changes of the glacier. Study suggest that warming induced initial increase of glacier degraded runoff and subsequent decline is a glaciers mass balance response and cannot be translated as river flow response in a ''Himalayan catchment'' as suggested by the IPCC, 2007. Study also suggest that the glacier runoff critically influence the headwater river flows during the years of low summer discharge and proposes that the Himalayan catchment could experience higher river flows and positive glacier mass balance regime together in association with strong monsoon. This paper intended to highlight the importance of creating credible knowledge on the Himalayan cryospheric processes to develop a global outlook on river flow response to cryospheric change and locally sustainable water resources management strategies.

scholarly journals An increasing role of pyrethroid-resistant Anopheles funestus in malaria transmission in the Lake Zone, Tanzania

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nancy S. Matowo ◽  
Jackline Martin ◽  
Manisha A. Kulkarni ◽  
Jacklin F. Mosha ◽  
Eliud Lukole ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Anopheles Funestus ◽  
Sub Saharan Africa ◽  
North West ◽  
Vector Population ◽  
Lake Zone ◽  
Sub Saharan ◽  
Long Lasting Insecticidal Nets ◽  
Study District

AbstractAnopheles funestus is playing an increasing role in malaria transmission in parts of sub-Saharan Africa, where An. gambiae s.s. has been effectively controlled by long-lasting insecticidal nets. We investigated vector population bionomics, insecticide resistance and malaria transmission dynamics in 86 study clusters in North-West Tanzania. An. funestus s.l. represented 94.5% (4740/5016) of all vectors and was responsible for the majority of malaria transmission (96.5%), with a sporozoite rate of 3.4% and average monthly entomological inoculation rate (EIR) of 4.57 per house. Micro-geographical heterogeneity in species composition, abundance and transmission was observed across the study district in relation to key ecological differences between northern and southern clusters, with significantly higher densities, proportions and EIR of An. funestus s.l. collected from the South. An. gambiae s.l. (5.5%) density, principally An. arabiensis (81.1%) and An. gambiae s.s. (18.9%), was much lower and closely correlated with seasonal rainfall. Both An. funestus s.l. and An. gambiae s.l. were similarly resistant to alpha-cypermethrin and permethrin. Overexpression of CYP9K1, CYP6P3, CYP6P4 and CYP6M2 and high L1014S-kdr mutation frequency were detected in An. gambiae s.s. populations. Study findings highlight the urgent need for novel vector control tools to tackle persistent malaria transmission in the Lake Region of Tanzania.

scholarly journals The role of accommodation environments in student mental health and wellbeing

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Joanne D. Worsley ◽  
Paula Harrison ◽  
Rhiannon Corcoran
Keyword(s):  
Mental Health ◽  
First Year ◽  
Student Mental Health ◽  
North West ◽  
Human Element ◽  
Health And Wellbeing ◽  
Physical Attributes ◽  
Attachment To Place ◽  
Pastoral Staff

Abstract Background Due to the increasing concern over student mental health and wellbeing, attention has turned to the matter of creating environments, communities, and institutions which enable students to flourish. Methods To explore the role of accommodation environments in first year student mental health and wellbeing, eight focus groups were conducted in two universities in North West England and analysed using thematic analysis. Results Three overarching themes were identified: ‘The betwixt space’; ‘Accommodations as vessels to cultivate friendships and communities’; and ‘The importance of accommodation-based pastoral staff’. As attachment to place and relationships with significant others are disrupted by the transition, this leaves young people vulnerable whilst they go through a process to re-attach to new people and a new environment, and loneliness and social isolation were keenly felt during this period. Physical attributes of place that prevent social cohesion further exacerbated feelings of loneliness. Conclusions As it is common for students to withdraw physically and psychologically when they do not form friendships within their flat, accommodation-based pastoral staff have an important role to fulfil. Although these findings demonstrate the importance of the human element within accommodation, designing places that facilitate community, a sense of we-ness, and belonging is crucial.

scholarly journals Surveying Potential Vectors of Apple Proliferation Phytoplasma: Faunistic Analysis and Infection Status of Selected Auchenorrhyncha Species

Insects ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Stefanie Fischnaller ◽  
Martin Parth ◽  
Manuel Messner ◽  
Robert Stocker ◽  
Christine Kerschbamer ◽  
...  
Keyword(s):  
New Records ◽  
Regional Scale ◽  
Insect Vectors ◽  
Infection Status ◽  
Apple Proliferation ◽  
Population Densities ◽  
South Tyrol ◽  
Candidatus Phytoplasma Mali ◽  
Cacopsylla Melanoneura

Apple proliferation (AP) is one of the economically most important diseases in European apple cultivation. The disease is caused by the cell-wall-less bacterium ’ Candidatus Phytoplasma mali’, which is transmitted by Cacopsylla picta (Foerster) and Cacopsylla melanoneura (Foerster) (Hemiptera: Psylloidea). In South Tyrol (Italy), severe outbreaks were documented since the 1990s. Infestation rates of AP do not always correlate with the population densities of the confirmed vectors, implying the presence of other, so far unknown, hemipterian vectors. By elucidating the species community of Auchenorrhyncha (Insecta: Hemiptera) at a regional scale, more than 31,000 specimens were captured in South Tyrolean apple orchards. The occurrence of 95 species was confirmed, whereas fourteen species are new records for this territory. Based on the faunistical data, more than 3600 individuals out of 25 species were analyzed using quantitative PCR to assess the presence of AP phytoplasma. The pathogen was sporadically detected in some individuals of different species, for example in Stictocephala bisonia Kopp and Yonk (Hemiptera: Membracidae). However, the concentration of phytoplasma was much lower than in infected C. picta and C. melanoneura captured in the same region, confirming the role of the latter mentioned psyllids as the main insect vectors of AP- phytoplasma in South Tyrol.

scholarly journals Arthropod community structure in pastures of an island archipelago (Azores): looking for local–regional species richness patterns at fine-scales

2004 ◽  
Vol 94 (2) ◽  
pp. 111-121 ◽  
Author(s):  
P.A.V. Borges ◽  
V.K. Brown
Keyword(s):  
Species Richness ◽  
Regional Scale ◽  
Local Scale ◽  
Local Species Richness ◽  
Β Diversity ◽  
Arthropod Species ◽  
Α Diversity ◽  
Local Species ◽  
Richness Patterns

AbstractThe arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local–regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= α diversity) and regional species richness was estimated at the pasture level (= γ diversity) with the ‘first-order-Jackknife’ estimator. Three related issues were addressed: (i) the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii) quantification of the relative contributions of α and β diversity to regional diversity using additive partitioning; and (iii) the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing β-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.

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